A new year is a time to look to the future and consolidate our experiences and aims.
I write, I teach and here I preach in the hope to clarify possibilities rather than simply criticise and to bring forward three topics for you to consider at the beginning of a new gardening year. Even though my three topics might appear random and unrelated: shrubs, plant communities and mycorrhizal fungi, I believe there is an underlying message.
I love a wide range of shrubs, but I have struggled over many years to use them effectively in my garden designs. This is partly because the information about them comes from experts who tend to be people who collect them into shrubberies and offer advice on their use only in terms of flowers, colour, form and leaf patterns. Invariably these shrubs grow larger than we are told and we all tend to plant one of each as either a specimen, or grouped to form a screen along our garden’s boundaries. Fortunately, here at Learning with Experts we have an exception to this in Andy McIndoe, who expertly shows us how to place and combine them with a wide range of other plants in our garden designs.
The naturalistic planting of the so-called Dutch Wave has also undervalued shrubs, banishing them from the fields of grasses and perennials, ever so popular nowadays in England and North America. What such plantings lack is year round structure and bold elements upon which the eye can rest; they need shrubs and trees - perennials alone are not enough both visually and ecologically.
Shrubs need pulling away from the boundaries of our gardens and placing within a community of other types of plants including other shrubs and perennials, to create planting schemes that function as a community. The shrubbery just as the perennial meadow are too one sided to be effective in the longer term.
This brings me to my second passion; we should be planting communities and not assembling borders of attractive plants selections based solely upon the mantra of “right plant, right place”. Of course growing conditions need to be appropriate for the plants we grow, but plants grow in nature in association with other species and have different strategies to enable them to coexist. To succeed some plants compete aggressively by overwhelming others with their rapid rate of growth either above or below ground. Other plants have evolved to grow in environments depleted in resources of one sort or another; these grow slowly in soils low in moisture or nutrients or they tolerate extreme weather conditions. Many of these are long lived and highly ornamental plants but they cannot compete with the aggressive competitors.
Inevitably, every plant in a natural community is there because they have found a way of using resources not being claimed by other plants in their vicinity. As gardeners we generally ignore such complex relationships and instead assemble plants into borders based upon aesthetic principles: colour, form, scale, texture etc.. Instead we need to keep competitors with competitors, and give the slower-growing stress-tolerators the space and time to establish and fully develop. We need to create planting schemes that utilise all resources available by layering plantings to occupy all visible levels within an ecosystem: using bulbs, mixtures of ground covering perennials, medium height perennials and shrubs as well as taller-growing shrubs and trees. By occupying each of these physical layers we start to create artificial plantings that reflect the same sorts of relationships found in natural plant communities which may serve the wider ecosystem beyond the boundaries of our gardens and not simply our own artistic aspirations.
Layers within natural plants communities occur not only above ground, but also below it and here is my third and most important message at the start of this new gardening year. The roots of plants grow to different depths taking up resources from different levels and thereby avoid direct competition with one another, however, they are not alone. As well as moles, mice, worms and insects every gardener knows something about the microorganisms found in healthy soils and we are all encouraged to promote these by adding the product of our compost heaps when planting or as an annual mulch.
Each of these organisms has a role to play in the soil’s ecosystem, but arguably the most import for us gardeners are the mycorrhizal fungi. These were once considered incidental and limited in their benefit to a small number of highly specialised plants such as orchids. Now we discover that there are hardly any plants growing in nature that do not rely heavily upon the fine network of filaments that mycorrhizal fungi weave throughout most soils.
Their importance to plants can be recognised by the revelation that some plants release up to 20% of the sugars and proteins they make from photosynthesis into the soil for the benefit of these fungi. In return they absorb water and mineral salts collected by fungal filaments extending significantly further out into the soil than their root systems are capable of reaching. Now, for example, we begin to understand why those plants in apparently dust dry soils can still stand upright.
These delicate fungi filaments are something we must cherish and nurture. When we dig the soil we break them apart and unfortunately they are slow to regrow. Artificial fertilisers also destroy mycorrhizal fungi and need avoiding as not only do these fungi feed and water the plants, they actively protect them against known soil pathogens. This knowledge, that has taken so long to filter through to the general gardening public, should help us revise the ways we garden in the future.
My three topics boil down to really just one thought. As gardeners we should not deny that the plants in our garden will form complex relationships with both one another and with the site in which we plant them. We should try to understand such relationships in order to allow them to thrive as part of a functioning community. and in so doing, they will in turn give us the maximum of pleasure. We might not be able to stop pruning, weeding and watering, but it will certainly cut down on the time we need to spend trying to tame the nature we unleash in our gardens.